In audio devices or other various electrical devices including a driving system, structural simplification and space reduction are required for the entire driving mechanism in order to promote scale reduction and operational reliability of the device. Such an intermittent gear mechanism including a single motor which drives two intermittent gears independently has been developed to meet the requirement.
Basic features of the intermittent gear mechanism is that two intermittent gears are opposedly disposed at opposite sides of a driving gear connected to a motor, and that sequential operation is repeated: i.e. while a first intermittent gear is driven, a second intermittent gear is held at a dormant position; and when the first intermittent gear approaches a dormant position, it is held in the dormant position, and the second intermittent gear is brought into an initial driving configuration from the dormant position.
In this connection, the intermittent gear mechanism needs holding means for holding the intermittent gears at dormant positions and initial driving means for bringing them into initial engagement with the driving gear. Usually, holding members using a biasing force of a resilient member are employed as the holding means. In order to move the intermittent gears from their dormant positions against the energy of the holding means, a forcible initial driving arrangement using a plunger or manual force has been employed heretofore. However, this arrangement invites dimensional increase and structural complication of the mechanism, and spoils one of the advantages of the intermittent gear mechanism. This drawback has been noted particularly in the field of car audio devices in which dimensional reduction is strongly required.